The present invention relates to encoders in general and, more particularly, to an error checking interface for encoders.
Encoders are widely used to determine the angular position of a rotating element. Various types of encoders are known to those in the industry and include widely used optical encoders. Typically, applications for such encoders include use on robot manipulators, machine tools and other mechansims employing position feedback.
Present encoder interfaces receive the encoder quadrature signals and use them to decode a count direction either up or down. In addition to the quadrature direction signals, present encoder interfaces also use an index Zdetection bit to indicate one complete revolution and continue counting. The nature of the low level signals from the optical encoder coupled with the deleterious environment in which they often operate makes then susceptible to electrical noise and prone to erroneous count sequences.
Accordingly, it is a general object of the present invention to provide an improved interface for encoders.
It is a specific object of the invention to provide an encoder interface that utilizes error checking by assuring that the proper number of counts are obtained for each revolution.
It is a further object of the invention to provide an encoder interface which produces error information to permit corrective action to be taken subsequently if an improper number of counts from the encoder is detected.